Urethane Vs Genuine Rubber Bushes.... opinions?

Post by **sonic23** » 06 Dec 2006, 14:44

Hi all,
As part of my Syncro rebuild - I'll be replacing all the bushes/bearings/ball joints in the front and rear suspension, where applicable.

Looking at the costs of genuine VW rubber bushes, I was contemplating getting one of Mr Baxter's Poly Bush kits for the Front as it seems quite reasonable - but I was just wondering what people thought about going down this road. Particularly with respect to longevity of urethane vs the rubber.

The rear doesn't appear to be of concern - as JK appear to do OEM bushes for approx £7

Any thoughts greatly appreciated?

cheers,
Rich

Post by **toomanytoys** » 06 Dec 2006, 16:18

Fit some to the arb mounts and the steering rack mounts... its amazing what difference that makes..
As for life.... dunno.. but I had heard that it doesnt last as long.. but have no proof of that... but if a lot cheaper!!! and easier... dunno...

Post by **bigbluebus** » 06 Dec 2006, 17:24

yeh I've full set on mine, noticeably better

no idea about life span

Post by **syncroandy** » 06 Dec 2006, 17:31

The original rubber bushes on my white van are still essentially fine after 15 years and 120,000 miles. VW seem to have got it right. You want to take a gamble and use another material that VW presumably rejected ? Some say poly bushes can break up quite quickly. One advantage of the lower TCA poly bushes is they are two-part so much easier to fit than the VW style ones.

I'd go for OEM rubber ones made by Febi. For the ball-joints, only use the best OEM (Febi again) or VW, as these are highly stressed parts, cheap ones are known to wear out prematurely. Having said that I do have a set of steering-rack poly bushes and will probably fit these as it seems a popular upgrade. Just my opinion.

Post by **syncropaddy** » 06 Dec 2006, 17:59

Go for the Set up that VW use. Poly bushes tend to wear out after a couple of years. Easier to fit alright and better feel but long life??? No

Post by **Simon Baxter** » 06 Dec 2006, 19:16

Worth a read.

http://www.powerflex.co.uk/faq.asp

One of the reasons I had them made is for the fact that customers seem to do a lot of their own repairs, by having the bottom arm bushes as a 2 piece item you can fit them with the arm in situ saving having to remove the arm, and having the new bushes pressed in, in a hydraulic press.

The rack bushes do take a lot of "slop" out of the steering and give a much more positive feel, you loose a lot of that woolyness you get with rubber.

The Cheap ARB link to bottom arm bushes don't last 2 minutes.

I like them, but I would say that wouldn't I!

Post by **Simon Baxter** » 06 Dec 2006, 19:17

On the subject of lifespan, a quote from Powerflex's website.

I love my car, it is a classic...What can they do for me?
Another major advantage of POWERFLEX bushes is life. Rubber is a natural product and deteriorates with age, especially on cars which are not being used regularly. The bushes will crack on the outer surface and soften inside. POWERFLEX bushes are not affected by ultra-violet, petrol, oil, battery acid, water or time. Prefect for your loved one. (And the car.)

Post by **toomanytoys** » 06 Dec 2006, 19:36

In total fairness, I should have added a comment to

As for life.... dunno.. but I had heard that it doesnt last as long.. but have no proof of that... but if a lot cheaper!!! and easier... dunno...

of
"from a hard used vehicle's owner"
but then the std items prob wouldnt last 2 minutes....

Post by **Trundler** » 06 Dec 2006, 22:47

I should start off by saying that I've no experience of this on a Type25, but...

On the quattro, urethane bushes make the car much noisier and less refined - I hated it. I now have genuine Audi rubber bushes - much better.

I also made the mistake of lowering the Audi. Never again. I'm now looking for some standard springs to restore the perfect compromise the car had before!

I'm really happy with the standard set up on the Syncro (considering what it is). The factory are no dummies

That's my conclusion!

Post by **HarryMann** » 07 Dec 2006, 02:55

As with most things, there are polybushes and there are polybushes..

I'm pretty sure I'm right saying they have improved a lot in the last 10 years or so... and a better understanding of the grades of urethane to use.

Some of the mfrs offer a variety of hardness ratings, and especially design specifically for leaf spring applications.

I cannot find much independent info on poor wear or low life.. quite the opposite, with most mfrs suggesting 6 to 10 times better life. But they would say that...

One problem that's pretty obvious is poor fitment, they need lube when fitting, maybe plenty of it, and Brickyard's Powerflex ones come with this in the kit, much like copperslip. Some designs may not fit that well, or even be designed incorrectly; but the main thing as with most rubber/flex bushes is to mount them unloaded in the car's basic suspension setting, that is, only nip them up properly only when the full weight is on the suspension.

The big question is, in suspension LCA applications, should they twist like rubber or should they spin in their housings? Some slight uncertainty there.

I can't necessarily agree with Andy that most of the rubber bushes on the T25 last 15 years, they might look like they do, but take the big front radius rod ones, they usually look fine, but just take them out and see the fretting inside against the spacer tubes (that usually have rusted to pieces, anyway) - replacing those with new rubber ones def. makes a difference after 15 years!

And T25 and esp, Syncro LCA bushes are well known for shuttling forward or rear in the housing, possibly due to bad fitment, possibly a life problem as they harden and shrink. This upsets the steering geometry badly. And replacement ARB drop-arm rubber bushes usually last 5 minutes... as was said above.

Anyone who knows Jaguars, the original XJ6 and XJS particularly will know that fantastic quiet, low NVH ride comes at a cost! A very expensive replacement of dozens of rubber bushes about every three or four years! Don't change them and the cars becomes abominal, uncertain sloppy steering, bump-steering and then eventually banging and knocking as they pack up totally... but then, some seem totally immune to such things

Fit hard polybushes (racing style ones) and NVH will approach that of metallic rose-joints; hopefully all the ones avaialble for T25s are a suitable compromise. The rack ones certainly tighten things up nicely, with a very slight increase in NVH I'd say. Can't see any problems with the ARB polybushes either.

But time will tell, with the LCA ones...

Post by **HarryMann** » 07 Dec 2006, 03:10

The most common mistake that people make when fitting and using urethane bushes is that they are compared to rubber bushes.
Polyurethane works in a completely different manner to rubber bushes, in that urethane slides on the surfaces of the pin/shackle and therefore requires the surfaces to be clean and smooth, and well lubricated.

When fitting shock absorbers with polyurethane bushes, do not over tighten the bushes. This will cause binding and will cause the shock absorber pin or eye mounts to break, voiding the warranty.

For pin mountings, tighten the nut until the bushes are just clamped up. Turn the nut no more than one full turn, and then fit and tighten the lock nut.
For eye mountings, when the mounting bolt is tightened, the shock absorber should be firm but not too tight. If the bushes are distorted, they are too tight and the bushes may have to be trimmed to suit the length of the mounting pin. Contact your ENFORCER distributor before modifying any component, as this will void all warranty.

I seem to remember than Old Man EMU shockers have polybushes rather than rubber?

Post by **Russel** » 07 Dec 2006, 06:40

My personal opinion.I would never fit them.Only use the original bushes and joints.(VW)
Consider this:When of roading ure suspension takes a lot of vibration and hard nocks(a lot of stress especialy with bigger tyres)
Where dose this all go?a lot is absorbed by the rubber bushes.
If u remove these and replace them with a hard material where dose all the unwanted shock go?to the subframe,welded joints,bolted joints and even to body panels.
In the long term this will cause unwanted stress and damage on ure vehicle that u sertainly dont want.
I have heard a lot of negative feedback from the offroad community about poly bushes.
I am not nocking this setup for road use though.

Post by **syncropaddy** » 07 Dec 2006, 08:35

Good point Russell. For general road use I would agree with Russ as the stresses and strains are completely different to off road use. As Simon indicates, the fitting of Poly bushes is quite simple and does not neccessitate special tools - ie press etc. Trundler also has a valid point which is one of my pet subjects - the factory knows best!! The best made van modified to 4x4 by the best off road specialist manufacturers cant have too many flaws in the running gear department and we all know that syncros are tough where it counts.
Stick to standard for off road use .........

Post by **bigbluebus** » 07 Dec 2006, 13:29

I wonder . . .

how 'hard' a brand new rubber bush is compared to a brand new poly bush

Post by **toomanytoys** » 07 Dec 2006, 15:00

go on Andy, buy some and see.....